Facebook's new Custom Audiences ad product allows advertisers to use your email address and phone numbers to target you with ads.

Basically, any company that already has an email list of its own customers can now take that list to Facebook, which will match it against a list of users who have those addresses. Those users then become ripe for targeting.

In a press release, AdParlor, a strategic preferred marketing partner (sPMP) for Facebook, announced that one of its large travel clients had successfully launched an email targeting campaign on Facebook that got a 25X return on investment from increased bookings, using the Custom Audiences tool to target their ads.

The tool was officially released to the public in September, and allows advertisers to use their CRM or non-Facebook contacts to target ads to Facebook users. The tool uses email addresses, phone numbers, and Facebook user IDs to match ads so advertisers can find the exact people they want to target.

This is how it works.

First, companies identify the groups of people they want to target through whatever type of CRM you use (Outlook, Salesforce, Gmail, an excel spreadsheet). Then, using Facebook's Power Editor (a Facebook tool for advertisers), advertisers input the contact information to find the individuals within the Facebook network.

Facebook "hashes" the data (a process that ensures personal contact information is kept anonymous) and matches the data to create a custom Facebook audience for your ads. These people do NOT have to be fans of your brand page.

To flesh out the list, you can also overlay it with Facebook location and demographic targeting. For now, the service is free for Facebook brands.

According to AdParlor, their first campaign using the Custom Audience product seems to have worked. For every $1 the AdParlor's travel client spent on Facebook Advertising, the Custom Audience campaign generated $25 in room booking revenue. “We are thrilled to see these results,” said Hussein Fazal, CEO of AdParlor. “This is further proof that Facebook can innovate with their advertising products to drive ROI positive ad spend and we expect more companies to begin leveraging this new targeting feature.”